This study tested whether overimitation is subject to an audience effect, and whether it is modulated by object novelty. A sample of 86 4- to 11-year-old children watched a demonstrator open novel and familiar boxes using sequences of necessary and unnecessary actions. The experimenter then observed the children, turned away, or left the room while the children opened the box. Children copied unnecessary actions more when the experimenter watched or when she left, but they copied less when she turned away. This parallels infant studies suggesting that turning away is interpreted as a signal of disengagement. Children displayed increased overimitation and reduced efficiency discrimination when opening novel boxes compared with familiar boxes. These data provide important evidence that object novelty is a critical component of overimitation